Petitjean M, Ripart J, Couture J, Bellemare F
Département d'Anesthésie-réanimation, Hôtel-Dieu de Montréal, Université de Montréal, Québec, Canada.
Am J Respir Crit Care Med. 1997 Mar;155(3):1162-6. doi: 10.1164/ajrccm.155.3.9117004.
Diaphragmatic phonomyogram (PMG) evoked by maximal bilateral phrenic nerve stimulation has previously been described as a good index of contractility of fresh and fatigued diaphragm. In the present study we hypothesized that diaphragmatic contractility changes could be even more simply evaluated by recording the relationship between the PMG and the compound motor action potential (CMAP) amplitudes during graded submaximal unilateral phrenic nerve stimulation at various intensities. Relationships between CMAPs and PMGs from left and right hemidiaphragms were recorded by means of surface electrodes and miniature microphones placed over the lower rib cage (eighth intercostal space) in five healthy subjects before and after a diaphragmatic fatigue task. These relationships in each subject were linear. The slope of these relationships decreased by 61.1 +/- 20.7% and by 70.4 +/- 14.6% on the right and left side respectively, but the intercepts did not change significantly. By comparison, transdiaphragmatic twitch pressure during maximal bilateral stimulation (PdiT) declined by 49.4 +/- 15%. We conclude that PMG during submaximal unilateral phrenic nerve stimulation is a reliable index of diaphragm contractility changes caused by fatigue. Using this method we have shown that all diaphragmatic motor units can be affected by fatigue.
最大双侧膈神经刺激诱发的膈肌音图（PMG）先前已被描述为新鲜和疲劳膈肌收缩力的良好指标。在本研究中，我们假设通过记录在不同强度的分级次最大单侧膈神经刺激期间PMG与复合运动动作电位（CMAP）幅度之间的关系，可以更简单地评估膈肌收缩力的变化。在五项健康受试者进行膈肌疲劳任务前后，通过放置在下胸廓（第八肋间间隙）的表面电极和微型麦克风记录左、右半膈肌的CMAP与PMG之间的关系。每个受试者的这些关系都是线性的。这些关系的斜率在右侧和左侧分别下降了61.1±20.7%和70.4±14.6%，但截距没有显著变化。相比之下，最大双侧刺激期间的经膈抽搐压力（PdiT）下降了49.4±15%。我们得出结论，次最大单侧膈神经刺激期间的PMG是疲劳引起的膈肌收缩力变化的可靠指标。使用这种方法我们已经表明，所有膈肌运动单位都可能受到疲劳的影响。
